MV design guide - Schneider Electric

Units
of measure
Names and symbols
of SI units of measure
Basic units
Magnitude Symbol of the magnitude 1 Unit Symbol of the unit Dimension
Basic units
length l, (L) metre m L
mass m kilogramme kg M
time t second s T
electrical current I ampere A I
thermodynamic temperature 2 T kelvin K θ
quantity of material n mole mol N
light intensity I, (Iv) candela cd J
Additional units
angle (plane angle) α, β, γ … radian rad N/A
solid angle Ω, (ω) steradian sr N/A
Common magnitudes and units
Name Symbol Dimension SI Unit: name Comments
(symbol)
and other units
Magnitude: space and time
length l, (L) L metre (m) centimetre (cm): 1 cm = 10 -2 m
(microns must no monger be used,
instead the micrometre (µm))
area A, (S) L 2 metre squared (m 2 ) are (a): 1 a = 10 2 m 2
hectare (ha): 1 ha = 10 4 m 2 (agricult. meas.)
volume V L 3 metre cubed (m 3 )
plane angle α, β, γ … N/A radian (rad) gradian (gr): 1 gr = 2π rad/400
revolution (rev): 1 tr = 2π rad
degree(°):1°= 2π rad/360 = 0.017 453 3 rad
minute ('): 1' = 2π rad/21 600
= 2,908 882 • 10 -4 rad
second ("): 1" = 2π rad/1 296 000
= 4.848 137 • 10 -6 rad
solid angle Ω, (ω) N/A steradian (sr)
time t T second (s) minute (mn)
hour (h)
day (d)
speed v L T -1 metre per second (m/s) revolutions per second (rev/s): 1 tr/s = 2π
rad/s
acceleration a L T -2 metre per second squared acceleration due to gravity:
(m/s 2 ) g = 9.80665 m/s 2
angular speed ω T -1 radian per second (rad/s)
angular acceleration α T -2 radian per second squared (rad/s 2 )
Magnitude: mass
mass m M kilogramme (kg) gramme (g) : 1 g = 10 -3 kg
ton (t) : 1 t = 10 3 kg
linear mass ρ1 L -1 M kilogramme per metre (kg/m)
mass per surface area ρA' (ρs) L -2 M kilogramme per metre squared (kg/m 2 )
mass per volume ρ L -3 M kilogramme per metre cubed (kg/m 3 )
volume per mass v L 3 M -1 metre cubed per kilogramme (m 3 /kg)
concentration ρB M L -3 kilogramme per metre cubed concentration by mass of component B
(kg/m 3 ) (according to NF X 02-208)
density d N/A N/A
Magnitude: periodic phenomena
period T T second (s)
frequency f T -1 hertz (Hz) 1 Hz = 1s -1 , f = 1/T
phase shift ϕ N/A radian (rad)
wavelength λ L metre (m) use of the angström (10 -10 m) is forbidden.
Use of a factor of nanometre
(10 9 m) is recommended λ = c/f = cT
(c = celerity of light)
power level Lp N/A decibel (dB)
e1
the symbol in brackets can also be used
2
the temperature Celsius t is related to the themrodynamic temperature T by the relationship: t = T - 273.15 K
Schneider Electric
Merlin Gerin MV design Guide
67